R. H. Whitehead 



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cytoplasmic network is much looser at the periphery of the cell than it 

 is around the nucleus; the meshes of the net seem to have been dis- 

 tended, and the coarse granules are very apparent at the nodal points. 

 As will be seen later, the same appearance, but in a much exaggerated 

 degree, is found in the last stages of the embryonic development of these 

 cells. During this period also the fixed connective-tissue cells begin 

 to build a delicate reticulum (Fig. 3). 



Following the stage shown in the embryo of 3.5 cm. there is a pro- 

 gressive decrease in the size of the Leydig's cells, the process affecting 



Fig. 4. Pig 5.5 cm. A group of tubules and an intertubular space. A quite per- 

 fect reticulum for the Leydig's cells has been formed. C.B., centrosphere B. ; Mal- 

 lory's connective-tissue stain. X 800. 



both the cell-body and the nucleus, though the change is more marked 

 in the former (Figs. 4 and 5). There is much condensation of the 

 cytoplasmic network, together with actual disappearance of cytoplasm. 

 This process reaches its acme in the pig of 14 cm (Fig. 5), where many 

 of the cells are reduced to their primitive condition of almost naked 

 nuclei. This change was noted by Allen (loc. cit,), but the term 

 " degeneration " employed by him scarcely seems appropriate ; atrophy 

 would doubtless be a more appropriate term. This atrophy, we shall 

 see, is merely temporary. Very few intertubular spaces can be found 

 which are as wide and contain as many and as large Leydig's cells as 

 the one represented in the figure; they are very scanty also beneath the 



